Hot-melt adhesive resin film and production method thereof

ABSTRACT

A hot-melt adhesive resin film includes a first adhesive layer, a first intermediate layer, a substrate layer having heat resistance, a second intermediate layer, and a second adhesive layer, which are laminated in this order, in which the first adhesive layer and the second adhesive layer include an acid-modified polyolefin resin.

CROSS REFERENCE TO RELATED APPLICATION

This Application is a Divisional of U.S. application Ser. No.15/748,990, filed Jan. 30, 2018, which is a National Phase ofPCL/IB2016/001087 filed on Aug. 3, 2016, which, in turn, claimed thepriority of Japanese Patent Application No. 2015-156366 which was filedon Aug. 6, 2015, the contents of which are all incorporated herein byreference.

TECHNICAL FIELD

The present invention relates to a hot-melt adhesive resin film havingexcellent adhesiveness to various adherends, particularly metal, and aproduction method thereof.

BACKGROUND TECHNOLOGY

Previously, as an adhesive film which adheres to an adherend, alaminated film composed of a three-layer structure in which athermosetting epoxy-based adhesive layer is formed on both sides of asubstrate consisting of a heat-resistant resin film, as described inPatent Document 1, has been known, but it was not sufficient, withrelation to adhesiveness to metal and durability.

Additionally, in the previous adhesive film, when adhesion with metal inparticular is performed, adhesiveness is not sufficient, andadhesiveness could not also be retained after the severe durabilityconditions. Additionally, in the previous adhesive film having nosubstrate, there was a problem that when prepared into a laminate, thestrength for keeping the laminate planar is not sufficient, anddistortion is generated in the laminate. On the other hand, there was aproblem that even when adhesion is performed using an adhesive filmhaving a substrate, peeling occurs between layers of a laminate, and thesufficient strength as an adhesive cannot be retained.

DOCUMENTS OF RELATED ART Patent Document

Patent Document 1: Japanese Unexamined Patent Application, FirstPublication No. 2013-028738

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

The present invention was made in view of the above-mentionedcircumstances, and an object thereof is to provide a hot-melt adhesiveresin film which does not cause peeling between respective layers, hasan excellent adhesive force, and has strong durability even in severedurability evaluation, to various planar or film-like adherends such asmetal, glass, and plastic, and a production method thereof.

Means for Solving the Problem

The present inventors investigated minutely and studied regarding anadhesive resin film also manifesting high durability in severerevaluation than before, to various planar or film-like adherends such asmetal, glass, and plastic, and found out the lamination configuration ofthe present invention, resulting in completion of the present invention.That is, the present inventors found out the configuration that aheat-resistant substrate is provided on a substrate layer to secure thestrength as a laminate, a resin layer having high adherence with asubstrate and high adherence with a surface layer is provided as anintermediate layer, acid-modified polyolefin is contained in a surfacelayer, and the acid-modified polyolefin in the surface layer securesadhesiveness with an adherend, resulting in completion of the presentinvention.

In order to solve the above-mentioned problems, the present inventionprovides a hot-melt adhesive resin film comprising a first adhesivelayer, a first intermediate layer, a substrate layer having heatresistance, a second intermediate layer, and a second adhesive layer,which are laminated in this order, wherein the first adhesive layer andthe second adhesive layer include an acid-modified polyolefin resin.

It is preferable that the first adhesive layer and the second adhesivelayer include, as a material for forming the layers, a compositionhaving an acid-modified polyolefin resin and an epoxy group-containingresin, or a composition having an acid-modified polyolefin resin and anoxazoline group-containing resin.

It is preferable that the first adhesive layer and the second adhesivelayer contain 80 parts by mass to 99.9 parts by mass of an acid-modifiedpolyolefin resin (A), and 0.1 parts by mass to 20 parts by mass of anepoxy group-containing polyolefin-based resin (B) having a main chainwhich is obtained by copolymerizing an olefin compound and an epoxygroup-containing vinyl monomer, and a side chain bound to the mainchain, and having a melting point of 80° C. to 120° C.

It is preferable that the first adhesive layer and the second adhesivelayer contain 90 parts by mass to 99.9 parts by mass of an acid-modifiedpolyolefin resin (A), and 0.1 parts by mass to 10 parts by mass of aphenol novolak-type epoxy resin (C) which is solid at an ambienttemperature.

It is preferable that the first adhesive layer and the second adhesivelayer contain 80 parts by mass to 99.9 parts by mass of an acid-modifiedpolyolefin resin (A), and 0.1 parts by mass to 20 parts by mass of anoxazoline group-containing styrene-based resin (D) having a numberaverage molecular weight of 50,000 to 250,000.

It is preferable that the first intermediate layer and the secondintermediate layer are at least one selected from the group consistingof polypropylene, metallocene-based polyethylene, and metallocene-basedpolypropylene, and a material for forming the substrate layer contains acyclic olefin polymer.

It is preferable that the first intermediate layer and the secondintermediate layer are at least one selected from the group consistingof a methylpentene polymer, a polybutene-based elastomer, andpolypropylene, and the substrate layer is formed of a methylpentenepolymer.

It is preferable that the substrate layer includes an inorganic filler.

Also, the present invention provides a method of producing theabove-mentioned hot-melt adhesive resin film, the method comprisingproducing the hot-melt adhesive resin film by a coextrusion method so asto laminate a first adhesive layer, a first intermediate layer, asubstrate layer having heat resistance, a second intermediate layer, anda second adhesive layer in this order.

Effects of Invention

According to the present invention, a hot-melt adhesive resin filmhaving an excellent adhesive force and durability, to various adherendssuch as metal, glass, and plastic can be provided. Particularly, ahot-melt adhesive resin film excellent in adhesion with metal can beprovided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing a schematic configuration of ahot-melt adhesive resin film which is one embodiment of the presentinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the hot-melt adhesive resin film of the presentinvention and a production method thereof will be illustrated.

In addition, the present embodiment more specifically illustrates thegist of the invention, but does not limit the present invention, unlessparticularly instructed.

[Hot-Melt Adhesive Resin Film]

FIG. 1 is a cross-sectional view showing a schematic configuration ofthe hot-melt adhesive resin film which is one embodiment of the presentinvention.

As shown in FIG. 1, a hot-melt adhesive resin film 10 of the presentembodiment comprises a substrate layer 11 having heat resistance, afirst intermediate layer 12 which is laminated on one side 11 a of thesubstrate layer 11, a second intermediate layer 13 which is laminated onthe other side 11 b of the substrate layer 11, a first adhesive layer 14which is laminated on a side (hereinafter, referred to as “one side”) 12a of the first intermediate layer 12 opposite to the substrate layer 11,and a second adhesive layer 15 which is laminated on a side(hereinafter, referred to as “one side”) 13 a of the second intermediatelayer 13 opposite to the substrate layer 11. That is, the hot-meltadhesive resin film 10 has the five-layer configuration that firstadhesive layer 14/first intermediate layer 12/substrate layer 11/secondintermediate layer 13/second adhesive layer 15 are laminated in thisorder as shown in FIG. 1.

A resin constituting the substrate layer 11 is not particularly limitedas far as it is a resin having sufficient heat resistance, and examplesthereof include synthetic resin films formed of polyester resins such aspolyethylene naphthalate (PEN), polyethylene terephthalate (PET), andpolybutylene terephthalate (PBT); polyolefin polymers such as a cyclicolefin polymer (COP) and a methylpentene polymer (TPX); and the like.

Among them, resins having a low linear expansion coefficient arepreferable.

By using resins having a low linear expansion coefficient, contractionof a laminate becomes small when the laminate is heated or cooled, and astrain of a laminate including metal becomes small.

As the resin used for the substrate layer 11, PEN, COP or TPX ispreferable, and COP or TPX is more preferable.

Additionally, as an additive, a particulate or fibrous filler can beintroduced into the substrate layer 11. The filler may be a fillerhaving high heat resistance, and includes an organic filler and aninorganic filler. By introducing the filler, a contractive force of thehot-melt adhesive resin film 10 can further be suppressed, and thestrength of the hot-melt adhesive resin film 10 itself can also beenhanced. In the present invention, it is preferable to add theinorganic filler from a view point of heat resistance and contractilityof the substrate layer.

Examples of the inorganic filler include carbonates such as calciumcarbonate, magnesium carbonate, and barium carbonate; sulfates such ascalcium sulfate, magnesium sulfate, and barium sulfate; chlorides suchas sodium chloride, calcium chloride, and magnesium chloride; oxidessuch as aluminum oxide, calcium oxide, magnesium oxide, zinc oxide,titanium oxide, and silica; minerals such as talc, smectite, mica, andkaolinite; carbon compounds such as carbon fiber and carbon particles;and fine particles consisting of glass. Additionally, examples of ashape include a spherical shape, a bar-like shape, a plate-like shapeand the like, and a plate-like compound is preferable.

A thickness of the substrate layer 11 is preferably 25 μm to 250 μm,more preferably 40 μm to 200 μm, and further preferably 70 μm to 190 μm.

Additionally, a thickness of the substrate layer 11 is preferably about20% to 70% of a thickness of a whole hot-melt adhesive resin film 10(that is, the total thickness of substrate layer 11, first intermediatelayer 12, second intermediate layer 13, first adhesive layer 14, andsecond adhesive layer 15).

The first intermediate layer 12 is a layer having adhesiveness to thesubstrate layer 11 and the first adhesive layer 14. On the other hand,the second intermediate layer 13 is a layer having adhesiveness to thesubstrate layer 11 and the second adhesive layer 15.

Adhesiveness which is required for the first intermediate layer 12 andthe second intermediate layer 13 refers to the strength for retainingthe strength as the laminate of the substrate layer 11 and the firstadhesive layer 14 or the second adhesive layer 15, and when adhesivenessis high, inter-layer peeling becomes difficult to occur.

A material constituting the first intermediate layer 12 and the secondintermediate layer 13 is not particularly limited, as far as the firstintermediate layer 12 and the second intermediate layer 13 have theabove-mentioned adhesiveness, but the material is appropriately selecteddepending on a material constituting the substrate layer 11.

When the material constituting the substrate layer 11 is a cyclic olefinpolymer (COP), the material constituting the first intermediate layer 12and the second intermediate layer 13 is preferably at least one selectedfrom the group consisting of acid-modified polypropylene,metallocene-based polyethylene, and metallocene-based polypropylene.That is, as the material constituting the first intermediate layer 12and the second intermediate layer 13, one selected from the groupconsisting of polypropylene, metallocene-based polyethylene, andmetallocene-based polypropylene may be used alone, or two or more may beused by combining them. Particularly, in order to prevent the occurrenceof inter-layer peeling, it is preferable that two or more are combined,and it is more preferable that three or more are contained.

For example, when the material constituting the first intermediate layer12 and the second intermediate layer 13 consists of three components ofacid-modified polypropylene, metallocene-based polyethylene, andmetallocene-based polypropylene, it is preferable that a blending amountof acid-modified polypropylene is 10 parts by mass to 40 parts by mass,a blending amount of metallocene-based polyethylene is 30 parts by massto 50 parts by mass, and a blending amount of metallocene-basedpolypropylene is 30 parts by mass to 40 parts by mass, and it isparticularly preferable that a blending amount of acid-modifiedpolypropylene is 20 parts by mass, a blending amount ofmetallocene-based polyethylene is 50 parts by mass, and a blendingamount of metallocene-based polypropylene is 30 parts by mass, when atotal of these three components is let to be 100 parts by mass.

Examples of acid-modified polypropylene include ADMER NB508, NF518,LB548, QB510, QB550, LB548, NE518, NF528, LF128, LF308, NF308, NF518,NF528, QF500, QF551, NF528, NF548, QF500, QF551, SF731, QF551, QF570,SF715, SF731, SE800, NF518, NF528, HE040, NE065, HE040, NE065, NE090,XE070, QE060, NR106, and NS101 manufactured by Mitsui Chemicals, Inc.,and the like.

Examples of metallocene-based polyethylene include Harmolex NF324A,NF375B, NT366A, NF384A, NF444A, NF464A, NC564A, NF325A, NF464A, NF444N,NH645A, NH745A, NH845N, and NJ744N manufactured by Japan PolyethyleneCorporation; EVOLUE SP0510, SP1020, SP1520, SP1210, SP2020, and SP2320manufactured by Prime Polymer Co., Ltd.; and the like.

Examples of metallocene-based polypropylene include WINTEC WFX6, WFW5T,WFX4M, WXK1233, WFX4TA, WFW4M, WMG3B, WMH02, WMX03, WSX02, WMG03, andWMG03UX manufactured by Japan Polypropylene Corporation, and the like.

When the resin constituting the substrate layer 11 is a methylpentenepolymer (TPX), it is preferable that the first intermediate layer 12 andthe second intermediate layer 13 are formed of at least one selectedfrom the group consisting of a methylpentene polymer, a polybutene-basedelastomer, and polypropylene. That is, as the resin constituting thefirst intermediate layer 12 and the second intermediate layer 13, atleast one selected from the group consisting of a methylpentene polymer,a polybutene-based elastomer, and polypropylene may be used alone, ortwo or more may be used by combining them. Particularly, in order toprevent the occurrence of inter-layer peeling, it is preferable tocombine three or more. In addition, as the methylpentene polymer, anacid-modified methylpentene polymer may be used.

For example, when the resin constituting the first intermediate layer 12and the second intermediate polymer 13 consists of four components of amethylpentene polymer, an acid-modified methylpentene polymer, apolybutene-based elastomer, and polypropylene, a blending amount of themethylpentene polymer is preferably 10 parts by mass to 70 parts by massand more preferably 20 parts by mass to 50 parts by mass, a blendingamount of the acid-modified methylpentene polymer is preferably 0 partsby mass to 50 parts by mass and more preferably more than 0 parts bymass and not more than 30 parts by mass, a blending amount of thepolybutene-based elastomer is preferably 5 parts by mass to 40 parts bymass and more preferably 10 parts by mass to 30 parts by mass, and ablending amount of polypropylene is preferably 5 parts by mass to 40parts by mass and more preferably 10 parts by mass to 30 parts by mass,when a total of these four components is let to be 100 parts by mass.

Examples of the methylpentene polymer include RT18, MX002, MX004, DX820,DX231, and DX310 manufactured by Mitsui Chemicals, Inc., and the like.

Examples of the polybutene-based elastomer include BL2491 and PB5640Mmanufactured by Mitsui Chemicals, Inc., and the like.

As polypropylene, maleic acid-modified polypropylene and randompolypropylene are suitably used.

A thickness of the first intermediate layer 12 and the secondintermediate layer 13 is preferably 0.1 μm to 5 μm and more preferably0.5 μm to 4 μm.

Additionally, a total thickness of the first intermediate layer 12 andthe second intermediate layer 13 is preferably about 5% to 40% of athickness of a whole hot-melt adhesive resin film 10 (that is, the totalthickness of substrate layer 11, first intermediate layer 12, secondintermediate layer 13, first adhesive layer 14, and second adhesivelayer 15).

The resin constituting the first intermediate layer 12 and the resinconstituting the second intermediate layer 13 may be the same ordifferent, in such a range that the first intermediate layer 12 and thesecond intermediate layer 13 satisfy the above-mentioned adhesiveness.

The first adhesive layer 14 and the second adhesive layer 15 are formedof a composition having an acid-modified polyolefin resin and an epoxygroup-containing resin or a composition having an acid-modifiedpolyolefin resin and an oxazoline group-containing resin. Moreparticularly, the first adhesive layer and the second adhesive layer areformed of a composition having an acid-modified polyolefin resin and anepoxy group-containing polyolefin-based resin (first adhesive resincomposition), a composition having an acid-modified polyolefin resin anda phenol novolak-type epoxy resin (second adhesive resin composition),or a composition having an acid-modified polyolefin resin and anoxazoline group-containing styrene-based resin (third adhesive resincomposition).

Plastic which is an adherend to be adhered using the hot-melt adhesiveresin film 10 of the present embodiment is not particularly limited, butadhesion with a polyolefin-based, polyester-based or polyamide-basedadherend is excellent.

A metal plate which is an adherend to be adhered using the hot-meltadhesive resin film 10 of the present embodiment is not particularlylimited, and the generally known metal plate, metal planar plate ormetal foil can be used. A metal of the metal plate may be, for example,iron, copper, aluminum, lead, zinc, titanium or chromium, or may bealloy such as stainless, or a metal or a non-metal, a surface of whichhas been treated by plating with metal or coating processing with apaint containing metal. Particularly preferable is a metal planar plateor a metal foil consisting of iron, aluminum, titanium, stainless or asurface-treated metal, and the firm adhesive strength can be realized.

[First Adhesive Resin Composition]

The first adhesive resin composition contains 80 parts by mass to 99.9parts by mass of an acid-modified polyolefin resin (A) and 0.1 parts bymass to 20 parts by mass of an epoxy group-containing polyolefin-basedresin (B) having a main chain which is obtained by copolymerizing anolefin compound and an epoxy group-containing vinyl monomer, and a sidechain bound to the main chain, and having a melting point of 80° C. to120° C.

Hereinafter, the acid-modified polyolefin resin (A) may be referred toas “(A) component”, and the epoxy group-containing polyolefin-basedresin (B) may be referred to as “(B) component”.

(Acid-Modified Polyolefin Resin (A))

In the first adhesive resin composition, the acid-modified polyolefinresin (A) is a polyolefin-based resin modified with unsaturatedcarboxylic acid or a derivative thereof, having an acid functional groupsuch as a carboxyl group or a carboxylic anhydride group in thepolyolefin-based resin.

The (A) component is obtained by modification of a polyolefin-basedresin with unsaturated carboxylic acid or a derivative thereof,copolymerization of an acid functional group-containing monomer andolefins, or the like. Among them, the (A) component which was obtainedby acid-modifying the polyolefin-based resin is preferable.

Examples of the add-modifying method include graft modification ofmelting and kneading the polyolefin resin and the acid functionalgroup-containing monomer in the presence of a radial polymerizationinitiator such as an organic peroxide or an aliphatic azo compound.

Examples of the above-mentioned polyolefin-based resin includepolyethylene, polypropylene, poly-1-butene, polyisobutylene, a randomcopolymer of propylene with ethylene or α-olefin, a block copolymer ofpropylene with ethylene or α-olefin, and the like. Among them, apolypropylene-based resin such as homopolypropylene (propylenehomopolymer; hereinafter, sometimes referred to as “homo PP”), apropylene-ethylene block copolymer (hereinafter, sometimes referred toas “block PP”), and a propylene-ethylene random copolymer (hereinafter,sometimes referred to as “random PP”) is preferable, and random PP isparticularly preferable.

Examples of the above-mentioned olefins when they are copolymerizedinclude olefin-based monomers such as ethylene, propylene, 1-butene,isobutylene, 1-hexene, and α-olefins.

The acid functional group-containing monomer is a compound having anethylenic double bond, and a carboxyl group or a carboxylic anhydridegroup in the same molecule, and examples thereof include variousunsaturated monocarboxylic acids, dicarboxylic acids, or acid anhydridesof dicarboxylic acids.

Examples of the acid functional group-containing monomer having acarboxyl group (carboxyl group-containing monomer) includeα,β-unsaturated carboxylic acid monomers such as acrylic acid,methacrylic acid, maleic acid, nadic acid, fumaric acid, itaconic acid,citraconic acid, crotonic acid, isocrotonic acid, tetrahydrophthalicacid, and endo-bicyclo[2.2.1]-5-heptene-2,3-dicarboxylic acid (endicacid).

Examples of the acid functional group-containing monomer having acarboxylic anhydride group (carboxylic anhydride group-containingmonomer) include unsaturated dicarboxylic anhydride monomers such asmaleic anhydride, nadic anhydride, itaconic anhydride, citraconicanhydride, and endic anhydride.

As these acid functional group-containing monomers, one may be usedalone, or two or more may be used by combining them, in the (A)component.

Among them, as the acid functional group-containing monomer, an acidfunctional group-containing monomer having an acid anhydride group ispreferable, a carboxylic anhydride group-containing monomer is morepreferable, and maleic anhydride is particularly preferable, due to highreactivity with a (B) component described later.

When a part of the acid functional group-containing monomer used inacid-modification is unreacted, it is preferable to use, as an (A)component, a component from which an unreacted acid functionalgroup-containing monomer has been removed in advance, in order toprevent reduction in an adhesive force due to an unreacted acidfunctional group-containing monomer.

In the (A) component, an amount of a component derived from thepolyolefin-based resin or olefins is preferably 50 parts by mass ormore, based on a total amount of 100 parts by mass of the (A) component.

A melting point of the (A) component is preferably 100° C. to 180° C.,in view of a temperature at which the (A) component and the (B)component described later are melted and kneaded. By using the (A)component having a melting point in the above-mentioned range, the (A)component and the (B) component described later can be melted andkneaded at a temperature sufficiently higher than a melting point of the(A) component, also when the conventional method and the generalapparatus are used. Additionally, when the (A) component and the (B)component described later are reacted by melting and kneading, it ispreferable that a melting point of the (B) component is lower ascompared with that of the (A) component, and a degree of freedom ofselection of the (B) component can be enhanced by using the (A)component having a melting point in the above-mentioned range.

Additionally, as described above, it is preferable that a melting pointof the (A) component is higher than a melting point of the (B) componentdescribed later, and a melting point of the (A) component is higher thana melting point of the (B) component more preferably by 10° C. or more,further preferably by 20° C. or more, and particularly preferably by 30°C. or more. By that a melting point of the (A) component is sufficientlyhigher than a melting point of the (B) component, upon melting andkneading, the (B) component is melted earlier, and permeated into the(A) component in the state where a shape of the resin is retained, toreact therewith uniformly, and as a result, good durability can beobtained.

Among them, as the (A) component, maleic anhydride-modifiedpolypropylene is preferable, from a viewpoint of adhesiveness and amoderate melting point.

(Epoxy Group-Containing Polyolefin-Based Resin (B))

In the first adhesive resin composition, the epoxy group-containingpolyolefin-based resin (B) is a resin having a main chain which isobtained by copolymerizing an olefin compound and an epoxygroup-containing vinyl monomer, and a side chain bound to the mainchain, and having a melting point of 80° C. to 120° C.

Main Chain

The main chain of the (B) component is obtained by copolymerizing anolefin compound, an epoxy group-containing vinyl monomer, and anotherarbitrary monomer which is used as needed.

Examples of the above-mentioned olefin compound include olefin-basedmonomers such as ethylene, propylene, 1-butene, isobutylene, 1-hexene,and α-olefin.

Examples of the above-mentioned epoxy group-containing vinyl monomerinclude glycidyl esters such as glycidyl methacrylate (GMA) and glycidylacrylate; glycidyl ethers such as allyl glycidyl ether; epoxyalkenessuch as epoxybutene; and the like.

As the olefin compound and the epoxy group-containing vinyl monomer, onemay be used alone, or two or more may be used by combining them,respectively.

The main chain of the (B) component may contain one or more othermonomers in addition to the olefin compound and the epoxygroup-containing vinyl monomer. Examples of other monomers are notparticularly limited, as far as they can be copolymerized with theolefin compound and the epoxy group-containing vinyl monomer, butinclude a (meth)acrylate monomer, a (meth)acrylic ester monomer, a(meth)acrylamide monomer, a styrene monomer, and the like.

In the copolymer which is to be the main chain of the (B) component, aconstituting ratio of each monomer (compound) is not particularlylimited, and a copolymer which is obtained by copolymerizing the epoxygroup-containing vinyl monomer at 10% by mass to 30% by mass, and morepreferably 10% by mass to 20% by mass, based on all monomersconstituting the main chain of the (B) component is preferable. By usingthe epoxy group-containing vinyl monomer in the above-mentioned range,adhesiveness with an adherend can be suitably improved.

Among them, as the main chain of the (B) component, a copolymer which isobtained by copolymerizing the olefin compound and the epoxygroup-containing vinyl monomer is preferable, and a copolymer ofethylene and glycidyl methacrylate is particularly preferable.

Side Chain

The (B) component can improve properties such as the strength,adhesiveness, and synthesis of the olefin-based copolymer, by having aside chain bound to the above-mentioned main chain. The side chain isnot particularly limited, but examples thereof include styrene-basedresins (polymers containing styrene) such as polystyrene and astyrene-acrylonitrile copolymer; (meth)acrylic-based resins which areobtained by polymerizing one or more of alkyl (meth)acrylate monomerssuch as methyl (meth)acrylate, ethyl (meth)acrylate, butyl(meth)acrylate, and pentyl (meth)acrylate; and the like.

Among them, as the side chain of the (B) component, polymers containingstyrene are preferable, and examples thereof include polystyrene and a.styrene-acrylonitrile copolymer. Among them, polystyrene is particularlypreferable.

The (B) component having the above-mentioned main chain and side chaincan be obtained, for example, by graft polymerization of a main chaincopolymer which was obtained by the conventional method, a monomerconstituting the side chain, and a radical polymerization initiator suchas an organic peroxide or an aliphatic azo compound.

A melting point of the (B) components is 80° C. to 120° C., andpreferably 90° C. to 110° C. The (B) component having such a meltingpoint can be obtained by appropriately selecting monomer speciesconstituting the main chain and the side chain.

By using the (B) component having a melting point in the above-mentionedrange, it becomes possible to melt and knead the above-mentioned (A)component and (B) component at a temperature sufficiently higher than amelting point of the relevant (B) component also when the conventionalmethod and the general apparatus are used, and an adhesive and anadhesive layer having excellent durability can be obtained.Additionally, when the above-mentioned (A) component and (B) componentare reacted using melting and kneading, it is preferable that a meltingpoint of the (B) component is lower as compared with that of the (A)component, and a degree of freedom of selection of the (A) component canbe enhanced by using the (B) component having a melting point in theabove-mentioned range.

As such (B) component, commercially available products such as ModiperA1100, A4100, and A4400 (all are product names) manufactured by NOFCORPORATION can also be used.

In the first adhesive resin composition, the (A) component is containedat 80 parts by mass to 99.9 parts by mass, whereas the (B) component iscontained at 0.1 parts by mass to 20 parts by mass. More specifically,it is preferable that a proportion of the (A) component is 90 parts bymass to 99 parts by mass and a proportion of the (B) component is 1 partby mass to 10 parts by mass in the solid contents of the first adhesiveresin composition.

If desired, a miscible additive, an additional resin, a plasticizer, astabilizer, a coloring agent, and the like can be appropriatelycontained in the first adhesive resin composition.

It is thought that both of an acid functional group of the (A) componentand an epoxy group of the (B) component function as adhesive functionalgroups to an adherend, and thereby, the first adhesive resin compositionbecomes possible to exert excellent adhesiveness to various adherendssuch as metal, glass, and plastic.

Additionally, it is thought that a part of an acid functional group ofthe (A) component and a part of an epoxy group of the (B) component arereacted to reinforce a dispersion structure of the (A) component and the(B) component, and thereby, good durability together with excellentadhesiveness is obtained.

[Second Adhesive Resin Composition]

The second adhesive resin composition contains 90 parts by mass to 99.9parts by mass of an acid-modified polyolefin resin (A) and 0.1 parts bymass to 10 parts by mass of a phenol novolak-type epoxy resin (C) whichis solid at an ambient temperature.

Hereinafter, the acid-modified polyolefin resin (A) may be referred toas “(A) component”, and the phenol novolak-type epoxy resin (C) may bereferred to as “(C) component”.

(Acid-Modified Polyolefin Resin (A))

In the second adhesive resin composition, the acid-modified polyolefinresin (A) is the same as the acid-modified polyolefin resin (A) in theabove-mentioned first adhesive resin composition.

(Phenol Novolak-Type Epoxy Resin (C))

In the second adhesive resin composition, the phenol novolak-type epoxyresin (C) is a phenol novolak-type epoxy resin which is solid at anambient temperature. By using the (C) component which is solid at anambient temperature, also when the above-mentioned (A) component and (C)component are polymerized by melting and kneading, melting and kneadingcan be performed in conformity with a melting temperature of the (A)component, and it allows properties of the (C) component to be hardlydeteriorated thereupon.

In addition, in the present specification, an “ambient temperature” isabout 3° C. to about 40° C., preferably about 10° C. to about 30° C.,more preferably about 15° C. to about 25° C., and most preferably about23° C.

In the second adhesive resin composition, the phenol novolak-type epoxyresin (C) is a polymer compound having a fundamental structure of aphenol novolak resin which is obtained by acid condensing phenol andformaldehyde, in which an epoxy group is introduced into a part of thestructure. An amount of an epoxy group to be introduced per one moleculein the phenol novolak-type epoxy resin is not particularly limited, andsince many epoxy groups are introduced into phenolic hydroxy groupsexisting at the great number in the phenol novolak resin by reacting anepoxy group raw material such as epichlorohydrin and a phenol novolakresin, the phenol novolak-type epoxy resin usually becomes apolyfunctional epoxy resin.

Among them, as the (C) component, a resin having a phenol novolakstructure as a fundamental skeleton as well as a bisphenol A structureis preferable. In addition, the bisphenol A structure in the (C)component may be a structure which can be derived from bisphenol A, andhydroxy groups at both ends of bisphenol A may have been substitutedwith a group such as an epoxy group-containing group.

One example of the (C) component includes a resin represented by thefollowing general formula (1).

[In the formula (1), R¹ to R⁶ are each independently a hydrogen atom ora methyl group, n is an integer of 0 to 10, and R^(X) is a group havingan epoxy group.]

In the above-mentioned general formula (1), R¹ to R⁶ are eachindependently a hydrogen atom or a methyl group. When n is an integer of2 or more, R³ and R⁴ may be the same or different.

It is preferable that the resin represented by the above-mentionedgeneral formula (1) satisfies at least any one of the following (i) to(iii).

(i) Both R¹ and R² are methyl groups.

(ii) Both R³ and R⁴ are methyl groups.

(iii) Both R⁵ and R⁶ are methyl groups.

For example, by satisfying the above-mentioned (i), it follows that acarbon atom to which R¹ and R² bind in the above-mentioned generalformula (1), and two hydroxyphenyl groups to which the relevant carbonatom bind, constitute a structure which is derived from bisphenol A.

In the above-mentioned general formula (1), R^(X) is a group having anepoxy group. Examples of the group having an epoxy group include anepoxy group, a combination of an epoxy group and an alkylene group, andthe like, and inter alia, a glycidyl group is preferable.

An epoxy equivalent of the (C) component is preferably 100 to 300, andmore preferably 200 to 300. An epoxy equivalent (g/eq) is a molecularweight of an epoxy resin per one epoxy group, and means that as thisvalue is smaller, the number of epoxy groups in the resin is larger. Byusing the (C) component having a relatively small epoxy equivalent, evenwhen an addition amount of the (C) component is relatively small,adhesiveness between the (C) component and an adherend becomes good, andthe (C) component and the above-mentioned (A) component are sufficientlycrosslinked.

As such (C) component, commercially available products such as jER154,jER157S70, and jER-157S65 manufactured by Mitsubishi ChemicalCorporation; EPICLON N-730A, EPICLON N-740, EPICLON N-770, and EPICLONN-775 manufactured by DIC CORPORATION (all are product names) can alsobe used.

In the second adhesive resin composition, it is preferable that the (A)component is contained at 90 parts by mass to 99.9 parts by mass,whereas the (C) component is contained at 0.1 parts by mass to 10 partsby mass, it is more preferable that the (A) component is contained at 95parts by mass to 99.9 parts by mass, whereas the (C) component iscontained at 0.1 parts by mass to 5 parts by mass, and it is furtherpreferable that the (A) component is contained at 97 parts by mass to 99parts by mass, whereas the (C) component is contained at 1 part by massto 3 parts by mass.

The second adhesive resin composition can appropriately contain amiscible additive, an additional resin, a plasticizer, a stabilizer, acoloring agent, and the like, if desired.

It is thought that both of an acid functional group of the (A) componentand an epoxy group of the (C) component function as adhesive functionalgroups to an adherend (particularly, functional group such as hydroxygroup possessed by adherend), and thereby, the second adhesive resincomposition becomes possible to exert excellent adhesiveness to variousadherends such as metal, glass, and plastic.

Additionally, it is thought that a part of an acid functional group ofthe (A) component and a part of an epoxy group of the (C) component arereacted to form a. crosslinked structure of the (A) component and the(C) component, the strength of the resin is reinforced by thiscrosslinked structure, and good durability together with excellentadhesiveness is obtained.

[Third Adhesive Resin Composition]

The third adhesive resin composition contains 80 parts by mass to 99.9parts by mass of an acid-modified polyolefin resin (A) and 0.1 parts bymass to 20 parts by mass of an oxazoline group-containing styrene-basedresin (D) having a number average molecular weight of 50,000 to 250,000.

Hereinafter, the acid-modified polyolefin resin (A) may be referred toas “(A) component”, and the oxazoline group-containing styrene-basedresin (D) may be referred to as “(D) component”.

(Acid-Modified Polyolefin Resin (A))

In the third adhesive resin composition, the acid-modified polyolefinresin (A) is the same as the acid-modified polyolefin resin (A) in theabove-mentioned first adhesive resin composition.

(Oxazoline Group-Containing Styrene-Based Resin (D))

In the third adhesive resin composition, the oxazoline group-containingstyrene-based resin (D) is an oxazoline group-containing styrene-basedresin having a number average molecular weight of 50,000 to 250,000.

By possession of an oxazoline group by the (D) component, the oxazolinegroup of the (D) component and the acid functional group (for example,carboxy group, carboxylic acid group, and the like) of theabove-mentioned (A) component are reacted to form a crosslinkedstructure. For example, in the case where the acid functional group ofthe (A) component is a carboxy group, a crosslinking reaction shown bythe following formula (2) occurs to form an amide ester bond. It isthought that, as a result, it follows that the (D) component reinforcesthe (A) component which is to be a main resin, crosslinking of the (A)component is more enhanced, and good durability together with excellentadhesiveness is obtained.

Among them, as the (D) component, a resin which is obtained bycopolymerizing a styrene-based monomer and an oxazoline group-containingmonomer is preferable.

As the styrene-based monomer, styrene and derivatives thereof can beused. Specifically, examples thereof include styrene; alkylstyrenes suchas □-methylstyrene, methylstyrene, dimethylstyrene, trimethylstyrene,ethylstyrene, diethylstyrene, triethyl styrene, propylstyrene,butylstyrene, hexylstyrene, heptyl styrene, and octylstyrene;halogenated styrenes such as chlorostyrene, fluorostyrene, bromostyrene,dibromostyrene, and iodostyrene; and the like. Among them, styrene ispreferable.

As far as the oxazoline group-containing monomer is a monomer whichcontains an oxazoline group and is copolymerizable with thestyrene-based monomer, a skeleton thereof is not particularly limited,and a monomer having an oxazoline group and a vinyl group can besuitably used.

Examples of the oxazoline group-containing vinyl monomer include2-vinyl-2-oxazoline, 5-methyl-2-vinyl-2-oxazoline,4,4-dimethyl-2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline,4,4-dimethyl-2-isopropenyl-2-oxazoline,4-acryloyl-oxymethyl-2,4-dimethyl-2-oxazoline,4-methacryloyloxymethyl-2,4-dimethyl-2-oxazoline,4-methacryloyloxymethyl-2-phenyl-4-methyl-2-oxazoline,2-(4-vinylphenyl)-4,4-dimethyl-2-oxazoline,4-ethyl-4-hyroxymethyl-2-isopropenyl-2-oxazoline,4-ethyl-4-carboethoxymethyl-2-isopropenyl-2-oxazoline, and the like.Among them, 2-isopropenyl-2-oxazoline is preferable.

As the styrene-based monomer and the oxazoline group-containing monomer,one may be used alone, or two or more may be used by combining them,respectively.

Additionally, the (D) component may contain one or more other monomers,in addition to the styrene-based monomer and the oxazolinegroup-containing monomer. Other monomers are not particularly limited asfar as they are copolymerizable with these monomers, and examplesthereof include a (meth)acrylate monomer, a (meth)acrylic ester monomer,a (meth)acrylamide monomer, and the like.

In the (D) component, a constituting ratio of each monomer is notparticularly limited, but a resin which is obtained by copolymerizingthe oxazoline group-containing monomer at 5% by mass to 50% by mass, andmore preferably 10% by mass to 30% by mass, based on all monomersconstituting the (D) component is preferable. By using the oxazolinegroup-containing monomer in the above-mentioned range, theabove-mentioned (A) component and (D) component can be sufficientlycrosslinked to obtain good durability.

A number average molecular weight of the (D) component is 50,000 to250,000, preferably 60,000 to 100,000, and further preferably 60,000 to80,000. By using the (D) component having a number average molecularweight in the above-mentioned range, compatibility between the (A)component and the (D) component is improved, and it becomes possible tosufficiently crosslink the (A) component and the (D) component.

As such (D) component, commercially available products such as EPOCROSRPS-1005 (product name) manufactured by NIPPON SHOKUBAI CO., LTD, can beused.

In the third adhesive resin composition, the (A) component is containedat 80 parts by mass to 99.9 parts by mass, whereas the (D) component iscontained at 0.1 parts by mass to 20 parts by mass. Inter glia, it ispreferable that the (A) component is contained at 95 parts by mass to 99parts by mass, whereas the (D) component is contained at 1 part by massto 5 parts by mass.

In the third adhesive resin composition, since an acid functional groupof the (A) component and an oxazoline group of the (D) component areeasily reacted by heating, it is not necessary to additionally blend acuring agent which can react with these functional groups, andoptionally, a miscible additive, an additional resin, a plasticizer, astabilizer, a coloring agent, and the like can be appropriatelycontained.

It is thought that an acid functional group of the (A) componentfunctions as an adhesive functional group to an adherend, and thereby,the third adhesive resin composition becomes possible to exert excellentadhesiveness to various adherends such as metal, glass, and plastic.Additionally, it is thought that a part of an acid functional group ofthe (A) component and a part of an oxazoline group of the (D) componentreact with each other to reinforce the (A) component which is to be amain resin, thereby, crosslinking of the (A) component becomes firmer,and good durability together with excellent adhesiveness can beobtained. In addition, when an adherend has a carboxyl group, theoxazoline group also functions as an adhesive functional group.

A thickness of each of the first adhesive layer 14 and the secondadhesive layer 15 is preferably 5 μm to 50 μm, and more preferably 10 μmto 30 μm.

Additionally, a total thickness of the first adhesive layer 14 and thesecond adhesive layer 15 is preferably about 5% to 60% of a thickness ofa whole hot-melt adhesive resin film 10 (that is, the total thickness ofsubstrate layer 11, first intermediate layer 12, second intermediatelayer 13, first adhesive layer 14, and second adhesive layer 15).

A resin constituting the first adhesive layer 14 and a resinconstituting the second adhesive layer 15 may be the same or differentin such a range that the first adhesive layer 14 and the second adhesivelayer 15 satisfy the above-mentioned adhesiveness.

Since the hot-melt adhesive resin film 10 of the present embodiment issuch that the first adhesive layer 14, the first intermediate layer 12,the substrate layer 11 having heat resistance, the second intermediatelayer 13, and the second adhesive layer 15 are laminated in this order,and the first adhesive layer 14 and the second adhesive layer 15 areformed of a composition having the acid-modified polyolefin resin andthe epoxy group-containing resin or a composition having theacid-modified polyolefin resin and the oxazoline group-containing resin,it has the excellent adhesive force and durability, to various adherendssuch as metal, glass, and plastic.

[Method of Producing Hot-Melt Adhesive Resin Film]

A method of producing the hot-melt adhesive resin film which is oneembodiment of the present invention includes, for example, a coextrusionmethod.

When the hot-melt adhesive resin film is produced using a coextrusionmethod, a resin constituting the substrate layer 11, a resinconstituting the first intermediate layer 12 and the second intermediatelayer 13, and a resin constituting the first adhesive layer 14 and thesecond adhesive layer 15 are each extruded from different extruders,respectively, these resins are laminated so as to be in an order offirst adhesive layer 14/first intermediate layer 12/substrate layer11/second intermediate layer 113/second adhesive layer 15 to form acomposite film in a die, and the composite film is stretched to obtain ahot-melt adhesive resin film 10 having a predetermined thickness.

When as the resin constituting the first intermediate layer 12 and thesecond intermediate layer 13, a plurality of materials is used bycombining them, those materials are melted and kneaded.

As an apparatus for melting and kneading, a single-screw extruder, amulti-screw extruder, a Banbury mixer, a plast mill, a heating rollkneader or the like can be used.

It is preferable that a heating temperature at melting and kneading isselected from such a range that the resin constituting the firstintermediate layer 12 and the second intermediate layer 13 issufficiently melted and not thermally degraded.

In addition, it is possible to measure a kneading temperature by amethod of contacting a resin composition in the melted state immediatelyafter extrusion from a melting and kneading apparatus, with athermocouple, or the like.

When as the resin constituting the first adhesive layer 14 and thesecond adhesive layer 15, a first adhesive resin composition is used, anacid-modified polyolefin resin (A) and an epoxy group-containingpolyolefin-based resin (B) are melted and kneaded.

The acid-modified polyolefin resin (A) and the epoxy group-containingpolyolefin-based resin (B) are the same as the above-mentioned (A)component and (B) component, respectively. By melting and kneading thefirst adhesive resin composition containing the above-mentioned (A)component and the above-mentioned (B) component using the knownapparatus, the (A) component and the (B) component can be reacted.

As an apparatus for melting and kneading, a single-screw extruder, amulti-screw extruder, a Banbury mixer, a plast mill, a heating rollkneader or the like can be used. In order to suppress degradation of anepoxy group of the (B) component at a reaction between the (A) componentand the (B) component, it is desirable that volatile components whichcan react with an epoxy group such as moisture are removed to theoutside of the apparatus in advance, and when volatile components aregenerated during a reaction, they are discharged to the outside of theapparatus by deaeration or the like as needed.

When the acid-modified polyolefin resin (A) has an acid anhydride groupas the acid functional group, this is preferable because reactivity withan epoxy group of the epoxy group-containing polyolefin-based resin (B)is high, and a reaction becomes possible under the milder condition.

A heating temperature at melting and kneading is preferably selectedfrom a range of 240° C. to 300° C. in point that the (A) component andthe (B) component are sufficiently melted and are not thermallydegraded.

In addition, it is possible to measure a kneading temperature by amethod of contacting the first adhesive resin composition in the meltedstate immediately after extrusion from a melting and kneading apparatus,with a thermocouple, or the like.

When as the resin constituting the first adhesive layer 14 and thesecond adhesive layer 15, the second adhesive resin composition is used,an acid-modified polyolefin resin (A) and a phenol novolak-type epoxyresin (C) are melted and kneaded.

The acid-modified polyolefin resin (A) and the phenol novolak-type epoxyresin (C) are the same as the above-mentioned (A) component and (C)component, respectively. By melting and kneading the second adhesiveresin composition containing the above-mentioned (A) component and theabove-mentioned (C) component using the known apparatus, the (A)component and the (C) component can be reacted.

As an apparatus for melting and kneading, a single-screw extruder, amulti-screw extruder, a Banbury mixer, a plast mill, a heating rollkneader or the like can be used. In order to suppress degradation of anepoxy group of the (C) component at a reaction between the (A) componentand the (C) component, it is desirable that volatile components whichcan react with an epoxy group such as moisture are removed to theoutside of an apparatus in advance, and when volatile components aregenerated during a reaction, they are discharged to the outside of theapparatus by deaeration or the like as needed.

When the acid-modified polyolefin resin (A) has an acid anhydride groupas the acid functional group, this is preferable because reactivity withan epoxy group of the phenol novolak-type epoxy resin (C) is high, and areaction becomes possible under the milder condition.

It is preferable that a heating temperature at melting and kneading isselected from a range of 240° C. to 300° C. in point that the (A)component and the (C) component are sufficiently melted and are notthermally degraded.

In addition, it is possible to measure a kneading temperature by amethod of contacting the second adhesive resin composition in the meltedstate immediately after extrusion from a melting and kneading apparatus,with a thermocouple, or the like.

When as the resin constituting the first adhesive layer 14 and thesecond adhesive layer 15, the third adhesive resin composition is used,an acid-modified polyolefin resin (A) and an oxazoline group-containingstyrene-based resin (D) are melted and kneaded.

The acid-modified polyolefin resin (A) and the oxazolinegroup-containing styrene-based resin (D) are the same as theabove-mentioned (A) component and (D) component, respectively. Bymelting and kneading the third adhesive resin composition containing theabove-mentioned (A) component and the above-mentioned (D) componentusing the known apparatus, the (A) component and the (D) component canbe reacted.

As an apparatus for melting and kneading, a single-screw extruder, amulti-screw extruder, a Banbury mixer, a plast mill, a heating rollkneader or the like can be used. In order to suppress degradation of anepoxy group of the (D) component at a reaction between the (A) componentand the (D) component, it is desirable that volatile components whichcan react with an epoxy group such as moisture are removed to theoutside of an apparatus in advance, and when volatile components aregenerated during a reaction, they are discharged to the outside of theapparatus by deaeration or the like as needed.

When the acid-modified polyolefin resin (A) has an acid anhydride groupas the acid functional group, this is preferable because reactivity withan oxazoline group of the phenol novolak-type epoxy resin (D) is high,and a reaction becomes possible under the milder condition.

It is preferable that a heating temperature at melting and kneading isselected from a range of 240° C. to 300° C. in point that the (A)component and the (D) component are sufficiently melted and are notthermally degraded.

In addition, it is possible to measure a kneading temperature by amethod of contacting the second adhesive resin composition in the meltedstate immediately after extrusion from a melting and kneading apparatus,with a thermocouple, or the like.

EXAMPLES

The present invention will be further specifically illustrated below byway of Examples, but the present invention is not limited to thefollowing Examples.

Examples 1 to 15 and Comparative Examples (Adhesive Resin Film)

After materials (a), (b), and (c) shown in Tables 1 and 2 were meltedand kneaded at 250° C. for 2 minutes at addition amounts shown in Tables1 and 2, five layers of a first adhesive layer, a first intermediatelayer, a substrate layer, a second intermediate layer, and a secondadhesive layer were formed into a film so that those layers werelaminated in this order, to obtain a hot-melt adhesive resin film havinga predetermined thickness. In addition, in Comparative Examples 2 and 3,three layers of a first adhesive layer, a substrate layer, and a secondadhesive layer were laminated in this order without providingintermediate layers. Film thickness of respective layers were 20 μm inthe first adhesive layer, 15 μm in the first intermediate layer, 75 μmin the substrate layer, 15 μm in the second intermediate layer, and 20μm in the second adhesive layer.

The material (a) is a material constituting the substrate layer, thematerial (b) is a material constituting the first intermediate layer andthe second intermediate layer, and the material (c) is a materialconstituting the first adhesive layer and the second adhesive layer.

In Table 1, each abbreviation has the following meaning, respectively, Anumerical value in [ ] is a blending amount (part by mass).

(Substrate Layer)

TPX: Layer formed of methylpentene polymer

COP: Layer formed of cyclic olefin polymer

CPP: Layer formed of polypropylene resin (PF380A, manufactured by SUNAROMA CO., LTD.)

In Table 2, a film was formed as a film including an inorganic filler ata described ratio.

(Adhesive Components)

(A): Maleic anhydride-modified polypropylene (melting point 140° C.)

(B): “Modiper A4100” (product name, manufactured by NOF CORPORATION)(graft polymer of ethylene-glycidyl methacrylate copolymer andpolystyrene; ratio of glycidyl methacrylate monomer based on allmonomers in main chain=70% by mass; melting point 97° C.)

(C) “jER157S70” (product name, manufactured by Mitsubishi ChemicalCorporation) (phenol novolak-type epoxy resin having bisphenol Astructure; softening point=70° C.; epoxy equivalent=210)

(D) “EPOCROS RPS-1005” (product name, manufactured by NIPPON SHOKUBAICO., LTD.) (resin which was obtained by copolymerizing styrene and2-isopropenyl-2-oxazoline; number average molecular weight=70,000)

(Intermediate Layer)

(E) SEBS resin G1657M (product name, Joseph Clayton & Sons, Ltd.)

(F) Metallocene-based polyethylene: Harmolex NF325N (product name,manufactured by Japan Polyethylene Corporation)

(G) Metallocene-based polypropylene: WINTEC WFW4 (product name,manufactured by Japan Polypropylene Corporation)

(H-I) Methylpentene polymer: MX004 (product name, manufactured by MitsuiChemicals, Inc.)

(I) Polybutene-based elastomer: BL2491 (product name, manufactured byMitsui Chemicals, Inc.)

(J) Polypropylene: ADMER QE060 (product name, manufactured by MitsuiChemicals, Inc.)

(Evaluation of Adhesiveness Between Metal, and First Adhesive Layer andSecond Adhesive Layer—Evaluation of Adhesiveness 1)

Each of adhesive resin films of Examples 1 to 12 and ComparativeExamples 1 to 5 which had been excised into 10 mm×10 mm was laminated ona stainless plate having a thickness of 5 mm, and a length and a widthof 30 mm×10 mm, an end part of an aluminum foil which had been cut intoa thickness of 30 μm, and a length and a width of 30 mm×10 mm was placedthereon, and they were stuck at 150° C. for 5 seconds while a pressureof 0.5 MPa was applied, and thereby, a laminate having an adhesion areaof 100 mm² was obtained.

The resulting laminate was soaked in hot water at 95° C. for 300 hours,an end part of the laminate after soaking was pulled with a clamp of atensile testing machine at a rate of 300 mm/min in a direction of 90°,and the peeled state was observed visually. The results are shown inTable 1.

Based on the following evaluation criteria, peeling between metal andthe laminate was observed.

◯: Peeling at an adhered surface between metal and the laminate did notoccur until an aluminum foil was ruptured.

Δ: Peeling slightly occurred at an adhered surface between metal and thelaminate before an aluminum foil was ruptured.

x: Peeling was easily generated at an adhered surface between metal andthe laminate before an aluminum foil was ruptured, and the peeling-offwas observed.

(Evaluation of Adhesiveness Between Layers of Adhesive ResinFilm—Evaluation of Adhesiveness 2)

Simultaneously with the above-mentioned evaluation of adhesivenessbetween metal, and first adhesive layer and second adhesive layer, thestate between layers of the laminate was observed and evaluated.

◯: Peeling between layers of the laminate did not occur until analuminum foil was ruptured.

Δ: Peeling occurred between layers of the laminate before an aluminumfoil was ruptured.

x: Peeling was easily generated in the laminate before an aluminum foilwas ruptured, and the peeling-off was observed.

In addition, in the case where both of evaluation of adhesiveness 1 andevaluation of adhesiveness 2 are “◯” in the evaluations of adhesiveness,this indicates that both of peeling between metal and the laminate andpeeling between layers of the laminate did not occur until an aluminumfoil was ruptured. In the case where there is “◯” in either ofevaluation of adhesiveness 1 or evaluation of adhesiveness 2, and thereis “Δ” or “x” in either of them, this indicates that either peeling wasobserved, or peeling was observed between layers of either of them.Additionally, in the case where there is “x” in both of evaluation ofadhesiveness 1 and evaluation of adhesiveness 2, this indicates thatintense peeling was observed between layers of all of them.

(Evaluation of Durability of Laminate)

Each of adhesive resin films of Examples 1 to 12 and ComparativeExamples 1 to 5 which had been excised into 10 mm×10 mm was laminated onan aluminum foil having a thickness of 30 μm and a length of 30 mm×awidth of 30 mm, an end part of a stainless foil which had been cut intoa thickness of 300 μm and a length of 30 mm×a width of 30 mm was placedthereon, and they were stuck at 150° C. for 5 seconds while a pressureof 0.5 MPa was applied, and thereby, a laminate was obtained.

The resulting laminate was placed into dried high temperature thermosequipment at 120° C. for 1,000 hours. After placement, the laminate wastaken out, the state of the laminate was observed, and peeling wasobserved visually. The results are shown in Table 1.

Evaluation was performed based on the following evaluation criteria.

⊙: There was no visible peeling and the state was good.

◯: Visible prominent peeling was not observed.

Δ: Peeling was observed at several places.

x: Peeling was observed on a whole surface.

(Shape Retainability at Adhesion)

Each of adhesive resin films of Examples 1 to 12 and ComparativeExamples 1 to 5 which had been excised into 10 mm×10 mm was laminated onan aluminum foil having a thickness of 30 μm and a length of 30 mm×awidth of 30 mm, an end part of a stainless foil which had been cut intoa thickness of 300 μm and a length of 30 mm×a width of 30 mm was placedthereon, and they were stuck at 150° C. for 5 seconds while a pressureof 0.5 MPa was applied, and thereby, a laminate was obtained.

The state of the laminate immediately after lamination was observedvisually, and the peeling-off was observed visually. The results areshown in Table 1.

Evaluation was performed based on the following evaluation criteria.

⊙: Visible distortion of the laminate was not observed.

◯: Visible intense distortion was not observed.

Δ: Distortion of the laminate was observed.

x: A whole surface of the laminate was intensely distorted orirregularities were intense.

TABLE 1 (b) Intermediate layer (c) (F) (G) (I) Adhesive (a) (E)Metallocene- Metallocene- (H) Polybutene- layer Substrate SEBS basedbased Methylpentene based (J) Resin layer resin polyethylenepolypropylene polymer elastomer Polypropylene component Example 1 TPX —— — [60] [20] [20] (A) [98.0] Example 2 TPX — — — [60] [20] [20] (A)[98.0] Example 3 TPX — — — [60] [20] [20] (A) [98.0] Example 4 TPX — — —[60] — [40] (A) [98.0] Example 5 COP [20] [50] [30] — — — (A) [98.0]Example 6 COP [20] [50] [30] — — — (A) [98.0] Example 7 COP [20] [50][30] — — — (A) [98.0] Example 8 COP [20] [30] [50] — — — (A) [98.0]Example 9 COP [100]  — — — — — (A) [98.0] Example 10 COP [20] [50] [30]— — — (A) [100]   Example 11 TPX — — — [60] [20] [20] (A) [100]  Comparative CPP [20] [50] [30] — — — (A) Example 1 [98.0] ComparativeTPX None (A) Example 2 [98.0] Comparative CPP None (A) Example 3 [98.0]Comparative TPX None (A) Example 4 [100]   Comparatve CPP None (A)Example 5 [100]   Evaluation results Evaluation of adhesiveness (c)between layers of Evaluation of Adhesive Evaluation of adhesivedurability layer adhesiveness between resin film - of laminate ShapeAdditive metal and evaluation of evaluation of retainability componentsurface layer adhesiveness 1 adhesiveness 2 at adhesion Example 1 (B) ◯◯ ◯ ⊙ [2.0] Example 2 (C) ◯ ◯ ◯ ⊙ [2.0] Example 3 (D) ◯ ◯ ◯ ◯ [2.0]Example 4 (B) ◯ Δ ◯ ◯ [2.0] Example 5 (B) ◯ ◯ ⊙ ⊙ [2.0] Example 6 (C) ◯◯ ⊙ ◯ [2.0] Example 7 (D) ◯ ◯ ⊙ ◯ [2.0] Example 8 (B) ◯ ◯ ⊙ ⊙ [2.0]Example 9 (B) ◯ Δ ◯ Δ [2.0] Example 10 — Δ ◯ Δ Δ Example 11 — Δ ◯ Δ ΔComparative (B) ◯ ◯ X X Example 1 [2.0] Comparative (B) ◯ X X Δ Example2 [2.0] Comparative (B) ◯ ◯ X X Example 3 [2.0] Comparative — X X X ΔExample 4 Comparatve — X ◯ X X Example 5

TABLE 2 (b) Intermediate layer (F) (G) (a) Substrate layer (E)Metallocene- Metallocene- (H) Inorganic SEBS based based MethylpentenePolymer filler resin polyethylene polypropylene polymer Example 12 COPNone [20] [50] [30] — Example 13 TPX None — — — [60] Example 14 COP Talc[20] [50] [30] — [10] Example 15 TPX Silica — — — [60] [10] Evaluation(b) Intermediate layer results (I) Shape Polybutene- (c) Adhesive layerretainability based (J) Resin Additive at elastomer Polypropylenecomponent component adhesion Example 12 — — (A) (B) ◯ [90.0] [10.0]Example 13 [20] [20] (A) (B) ◯ [90.0] [10.0] Example 14 — — (A) (B) ⊙[90.0] [10.0] Example 15 [20] [20] (A) (B) ⊙ [90.0] [10.0]

From the results shown in Table 1, it could be confirmed in evaluationof the laminate using the hot-melt adhesive resin film of the presentinvention that the hot-melt adhesive resin film of the present inventionhas excellent adhesiveness to metal. Additionally, it could also beconfirmed that the laminate using the adhesive resin film of the presentinvention has good adhesion between metal and the adhesive layer, andalso has excellent adhesiveness between layers of the hot-melt adhesiveresin film. It could be confirmed that the film and the laminate haveexcellent durability even after severe durability evaluation, and it wasseen that the hot-melt adhesive resin film is hardly warped, and thepresent adhesive resin film is a hot-melt adhesive resin film which isalso useful in production of the laminate.

In Comparative Examples 1, 3, and 5, the substrate layer includes anundrawn polypropylene film, and it was seen that adhesiveness betweenthe intermediate layer or the surface layer is good due to beingpolypropylene, but since undrawn polypropylene is a material having lowheat resistance, a thickness and a shape of the laminate could not beretained.

Additionally, in Comparative Examples 2 and 4, the substrate layerincludes an undrawn polypropylene film, and it was seen that sinceundrawn polypropylene is a material having low heat resistance,distortion is seen in the laminate after lamination, or there isunevenness in a thickness, and a shape cannot be retained.

Since the hot-melt adhesive resin films of Example 11 and Example 1.2 donot include an additive component in the adhesive layer, adhesivenesswith the metal layer was inferior as compared with Examples 1 to 10.

From the results shown in Table 2, it was seen that shape retainabilityat adhesion is improved by inclusion of the inorganic filler in thesubstrate layer.

1. A hot-melt adhesive resin film comprising a first adhesive layer, afirst intermediate layer, a substrate layer having heat resistance, asecond intermediate layer, and a second adhesive layer, which arelaminated in this order, wherein said first adhesive layer and saidsecond adhesive layer include an acid-modified polyolefin resin (A)having a melting point of 140° C. to 180° C., and said substrate layeris a layer formed of methylpentene polymer.
 2. The hot-melt adhesiveresin film according to claim 1, wherein said first adhesive layer andsaid second adhesive layer include, as a material for forming thelayers, a composition having the acid-modified polyolefin resin (A) andan epoxy group-containing resin or a composition having theacid-modified polyolefin resin (A) and an oxazoline group-containingresin.
 3. The hot-melt adhesive resin film according to claim 1, whereinsaid first adhesive layer and said second adhesive layer contain 80parts by mass to 99.9 parts by mass of the acid-modified polyolefinresin (A), and 0.1 parts by mass to 20 parts by mass of an epoxygroup-containing polyolefin-based resin (B) having a main chain which isobtained by copolymerizing an olefin compound and an epoxygroup-containing vinyl monomer and a side chain bound to said mainchain, and having a melting point of 80° C. to 120° C.
 4. The hot-meltadhesive resin film according to claim 1, wherein said first adhesivelayer and said second adhesive layer contain 90 parts by mass to 99.9parts by mass of the acid-modified polyolefin resin (A), and 0.1 partsby mass to 10 parts by mass of a phenol novolak-type epoxy resin (C)which is solid at an ambient temperature
 5. The hot-melt adhesive resinfilm according to claim 1, wherein said first adhesive layer and saidsecond adhesive layer contain 80 parts by mass to 99.9 parts by mass ofthe acid-modified polyolefin resin (A), and 0.1 parts by mass to 20parts by mass of an oxazoline group-containing styrene-based resin (D)having a number average molecular weight of 50,000 to 250,000.
 6. Thehot-melt adhesive resin film according to claim 1, wherein said firstintermediate layer and said second intermediate layer are at least oneselected from the group consisting of a methylpentene polymer, apolybutene-based elastomer, and polypropylene.
 7. The hot-melt adhesiveresin film according to claim 1, wherein said substrate layer comprisesan inorganic filler.
 8. A method of producing the hot-melt adhesiveresin film as defined in claim 1, the method comprising producing thehot-melt adhesive resin film by a coextrusion method so as to laminatethe first adhesive layer, the first intermediate layer, the substratelayer having heat resistance, the second intermediate layer, and thesecond adhesive layer in this order.